Generation of plants with altered oil content

ABSTRACT

The present invention is directed to plants that display an altered oil content phenotype due to altered expression of a HIO32.2 nucleic acid. The invention is furthered directed to methods of generating plants with an altered oil content phenotype.

REFERENCE TO RELATED APPLICATIONS

This is the § 371 U.S. National Stage of International Application No. PCT/US2004/042749, filed on Dec. 17, 2004, which was published in English under PCT Article 21(2), and which in turn claims the benefit of U.S. Provisional Patent Application No. 60/530,878, filed Dec. 17, 2003, both of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

The ability to manipulate the composition of crop seeds, particularly the content and composition of seed oils, has important applications in the agricultural industries, relating both to processed food oils and to oils for animal feeding. Seeds of agricultural crops contain a variety of valuable constituents, including oil, protein and starch. Industrial processing can separate some or all of these constituents for individual sale in specific applications. For instance, nearly 60% of the U.S. soybean crop is crushed by the soy processing industry. Soy processing yields purified oil, which is sold at high value, while the remainder is sold principally for lower value livestock feed (U.S. Soybean Board, 2001 Soy Stats). Canola seed is crushed to produce oil and the co-product canola meal (Canola Council of Canada). Nearly 20% of the 1999/2000 U.S. corn crop was industrially refined, primarily for production of starch, ethanol and oil (Corn Refiners Association). Thus, it is often desirable to maximize oil content of seeds. For instance, for processed oilseeds such as soy and canola, increasing the absolute oil content of the seed will increase the value of such grains. For processed corn it may be desired to either increase or decrease oil content, depending on utilization of other major constituents. Decreasing oil may improve the quality of isolated starch by reducing undesired flavors associated with oil oxidation. Alternatively, in ethanol production, where flavor is unimportant, increasing oil content may increase overall value. In many fed grains, such as corn and wheat, it is desirable to increase seed oil content, because oil has higher energy content than other seed constituents such as carbohydrate. Oilseed processing, like most grain processing businesses, is a capital-intensive business; thus small shifts in the distribution of products from the low valued components to the high value oil component can have substantial economic impacts for grain processors.

Biotechnological manipulation of oils can provide compositional alteration and improvement of oil yield. Compositional alterations include high oleic soybean and corn oil (U.S. Pat. Nos. 6,229,033 and 6,248,939), and laurate-containing seeds (U.S. Pat. No. 5,639,790), among others. Work in compositional alteration has predominantly focused on processed oilseeds but has been readily extendable to non-oilseed crops, including corn. While there is considerable interest in increasing oil content, the only currently practiced biotechnology in this area is High-Oil Corn (HOC) technology (DuPont, U.S. Pat. No. 5,704,160). HOC employs high oil pollinators developed by classical selection breeding along with elite (male-sterile) hybrid females in a production system referred to as TopCross. The TopCross High Oil system raises harvested grain oil content in maize from about 3.5% to about 7%, improving the energy content of the grain.

While it has been fruitful, the HOC production system has inherent limitations. First, the system of having a low percentage of pollinators responsible for an entire field's seed set contains inherent risks, particularly in drought years. Second, oil contents in current HOC fields have plateaued at about 9% oil. Finally, high-oil corn is not primarily a biochemical change, but rather an anatomical mutant (increased embryo size) that has the indirect result of increasing oil content. For these reasons, an alternative high oil strategy, particularly one that derives from an altered biochemical output, would be especially valuable.

The most obvious target crops for the processed oil market are soy and rapeseed, and a large body of commercial work (e.g., U.S. Pat. No. 5,952,544; PCT application WO9411516) demonstrates that Arabidopsis is an excellent model for oil metabolism in these crops. Biochemical screens of seed oil composition have identified Arabidopsis genes for many critical biosynthetic enzymes and have led to identification of agronomically important gene orthologs. For instance, screens using chemically mutagenized populations have identified lipid mutants whose seeds display altered fatty acid composition (Lemieux et al., 1990; James and Dooner, 1990). T-DNA mutagenesis screens (Feldmann et al., 1989) that detected altered fatty acid composition identified the omega 3 desaturase (FAD3) and delta-12 desaturase (FAD2) genes (U.S. Pat. No. 5,952,544; Yadav et al., 1993; Okuley et al., 1994). A screen which focused on oil content rather than oil quality, analyzed chemically-induced mutants for wrinkled seeds or altered seed density, from which altered seed oil content was inferred (socks and Benning, 1998). Another screen, designed to identify enzymes involved in production of very long chain fatty acids, identified a mutation in the gene encoding a diacylglycerol acyltransferase (DGAT) as being responsible for reduced triacyl glycerol accumulation in seeds (Katavic V et al, 1995). It was further shown that seed-specific over-expression of the DGAT cDNA was associated with increased seed oil content (Jako et al., 2001).

Activation tagging in plants refers to a method of generating random mutations by insertion of a heterologous nucleic acid construct comprising regulatory sequences (e.g., an enhancer) into a plant genome. The regulatory sequences can act to enhance transcription of one or more native plant genes; accordingly, activation tagging is a fruitful method for generating gain-of-function, generally dominant mutants (see, e.g., Hayashi et al., 1992; Weigel D et al. 2000). The inserted construct provides a molecular tag for rapid identification of the native plant whose mis-expression causes the mutant phenotype. Activation tagging may also cause loss-of-function phenotypes. The insertion may result in disruption of a native plant gene, in which case the phenotype is generally recessive.

Activation tagging has been used in various species, including tobacco and Arabidopsis, to identify many different kinds of mutant phenotypes and the genes associated with these phenotypes (Wilson et al., 1996, Schaffer et al., 1998, Fridborg et al., 1999; Kardailsky et al., 1999; Christensen S et al. 1998).

SUMMARY OF THE INVENTION

The invention provides a transgenic plant having a high oil phenotype. The transgenic plant comprises a transformation vector comprising a nucleotide sequence that encodes or is complementary to a sequence that encodes a HIO32.2 polypeptide comprising the amino acid sequence of SEQ ID NO:2, or an ortholog thereof. In preferred embodiments, the transgenic plant is selected from the group consisting of rapeseed, soy, corn, sunflower, cotton, cocoa, safflower, oil palm, coconut palm, flax, castor and peanut. The invention also provides a method of producing oil comprising growing the transgenic plant and recovering oil from said plant. The invention further provides a method of generating a plant having a high oil phenotype by identifying a plant that has an allele in its HIO30.4 gene that results in increased oil content compared to plants lacking the allele and generating progeny of the identified plant, wherein the generated progeny inherit the allele and have the high oil phenotype.

The transgenic plant of the invention is produced by a method that comprises introducing into progenitor cells of the plant a plant transformation vector comprising a nucleotide sequence that encodes or is complementary to a sequence that encodes a HIO32.2 polypeptide, and growing the transformed progenitor cells to produce a transgenic plant, wherein the HIO32.2 polynucleotide sequence is expressed causing the high oil phenotype.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as they would to one skilled in the art of the present invention. Practitioners are particularly directed to Sambrook et al., 1989, and Ausubel F M et al., 1993, for definitions and terms of the art. It is to be understood that this invention is not limited to the particular methodology, protocols, and reagents described, as these may vary.

As used herein, the term “vector” refers to a nucleic acid construct designed for transfer between different host cells. An “expression vector” refers to a vector that has the ability to incorporate and express heterologous DNA fragments in a foreign cell. Many prokaryotic and eukaryotic expression vectors are commercially available. Selection of appropriate expression vectors is within the knowledge of those having skill in the art.

A “heterologous” nucleic acid construct or sequence has a portion of the sequence that is not native to the plant cell in which it is expressed. Heterologous, with respect to a control sequence refers to a control sequence (i.e. promoter or enhancer) that does not function in nature to regulate the same gene the expression of which it is currently regulating. Generally, heterologous nucleic acid sequences are not endogenous to the cell or part of the genome in which they are present, and have been added to the cell, by infection, transfection, microinjection, electroporation, or the like. A “heterologous” nucleic acid construct may contain a control sequence/DNA coding sequence combination that is the same as, or different from a control sequence/DNA coding sequence combination found in the native plant.

As used herein, the term “gene” means the segment of DNA involved in producing a polypeptide chain, which may or may not include regions preceding and following the coding region, e.g. 5′ untranslated (5′ UTR) or “leader” sequences and 3′ UTR or “trailer” sequences, as well as intervening sequences (introns) between individual coding segments (exons) and non-transcribed regulatory sequence.

As used herein, “recombinant” includes reference to a cell or vector, that has been modified by the introduction of a heterologous nucleic acid sequence or that the cell is derived from a cell so modified. Thus, for example, recombinant cells express genes that are not found in identical form within the native (non-recombinant) form of the cell or express native genes that are otherwise abnormally expressed, under expressed or not expressed at all as a result of deliberate human intervention.

As used herein, the term “gene expression” refers to the process by which a polypeptide is produced based on the nucleic acid sequence of a gene. The process includes both transcription and translation; accordingly, “expression” may refer to either a polynucleotide or polypeptide sequence, or both. Sometimes, expression of a polynucleotide sequence will not lead to protein translation. “Over-expression” refers to increased expression of a polynucleotide and/or polypeptide sequence relative to its expression in a wild-type (or other reference [e.g., non-transgenic]) plant and may relate to a naturally-occurring or non-naturally occurring sequence. “Ectopic expression” refers to expression at a time, place, and/or increased level that does not naturally occur in the non-altered or wild-type plant. “Under-expression” refers to decreased expression of a polynucleotide and/or polypeptide sequence, generally of an endogenous gene, relative to its expression in a wild-type plant. The terms “mis-expression” and “altered expression” encompass over-expression, under-expression, and ectopic expression.

The term “introduced” in the context of inserting a nucleic acid sequence into a cell, means “transfection”, or “transformation” or “transduction” and includes reference to the incorporation of a nucleic acid sequence into a eukaryotic or prokaryotic cell where the nucleic acid sequence may be incorporated into the genome of the cell (for example, chromosome, plasmid, plastid, or mitochondrial DNA), converted into an autonomous replicon, or transiently expressed (for example, transfected mRNA).

As used herein, a “plant cell” refers to any cell derived from a plant, including cells from undifferentiated tissue (e.g., callus) as well as plant seeds, pollen, progagules and embryos.

As used herein, the terms “native” and “wild-type” relative to a given plant trait or phenotype refers to the form in which that trait or phenotype is found in the same variety of plant in nature.

As used herein, the term “modified” regarding a plant trait, refers to a change in the phenotype of a transgenic plant relative to the similar non-transgenic plant. An “interesting phenotype (trait)” with reference to a transgenic plant refers to an observable or measurable phenotype demonstrated by a T1 and/or subsequent generation plant, which is not displayed by the corresponding non-transgenic (i.e., a genotypically similar plant that has been raised or assayed under similar conditions). An interesting phenotype may represent an improvement in the plant or may provide a means to produce improvements in other plants. An “improvement” is a feature that may enhance the utility of a plant species or variety by providing the plant with a unique and/or novel quality. An “altered oil content phenotype” refers to measurable phenotype of a genetically modified plant, where the plant displays a statistically significant increase or decrease in overall oil content (i.e., the percentage of seed mass that is oil), as compared to the similar, but non-modified plant. A high oil phenotype refers to an increase in overall oil content.

As used herein, a “mutant” polynucleotide sequence or gene differs from the corresponding wild type polynucleotide sequence or gene either in terms of sequence or expression, where the difference contributes to a modified plant phenotype or trait. Relative to a plant or plant line, the term “mutant” refers to a plant or plant line which has a modified plant phenotype or trait, where the modified phenotype or trait is associated with the modified expression of a wild type polynucleotide sequence or gene.

As used herein, the term “T1” refers to the generation of plants from the seed of T0 plants. The T1 generation is the first set of transformed plants that can be selected by application of a selection agent, e.g., an antibiotic or herbicide, for which the transgenic plant contains the corresponding resistance gene. The term “T2” refers to the generation of plants by self-fertilization of the flowers of T1 plants, previously selected as being transgenic. T3 plants are generated from T2 plants, etc. As used herein, the “direct progeny” of a given plant derives from the seed (or, sometimes, other tissue) of that plant and is in the immediately subsequent generation; for instance, for a given lineage, a T2 plant is the direct progeny of a T1 plant. The “indirect progeny” of a given plant derives from the seed (or other tissue) of the direct progeny of that plant, or from the seed (or other tissue) of subsequent generations in that lineage; for instance, a T3 plant is the indirect progeny of a T1 plant.

As used herein, the term “plant part” includes any plant organ or tissue, including, without limitation, seeds, embryos, meristematic regions, callus tissue, leaves, roots, shoots, gametophytes, sporophytes, pollen, and microspores. Plant cells can be obtained from any plant organ or tissue and cultures prepared therefrom. The class of plants which can be used in the methods of the present invention is generally as broad as the class of higher plants amenable to transformation techniques, including both monocotyledenous and dicotyledenous plants.

As used herein, “transgenic plant” includes a plant that comprises within its genome a heterologous polynucleotide. The heterologous polynucleotide can be either stably integrated into the genome, or can be extra-chromosomal. Preferably, the polynucleotide of the present invention is stably integrated into the genome such that the polynucleotide is passed on to successive generations. A plant cell, tissue, organ, or plant into which the heterologous polynucleotides have been introduced is considered “transformed”, “transfected”, or “transgenic”. Direct and indirect progeny of transformed plants or plant cells that also contain the heterologous polynucleotide are also considered transgenic.

Identification of Plants with an Altered Oil Content Phenotype

We used an Arabidopsis activation tagging screen to identify the association between the gene we have designated “HIO32.2,” (At3g47710; GI#22331644 encoding protein T23J7.40 (GI#22331654), and an altered oil content phenotype (specifically, a high oil phenotype). Briefly, and as further described in the Examples, a large number of Arabidopsis plants were mutated by transformation with the pSKI015 vector, which comprises a T-DNA from the Ti plasmid of Agrobacterium tumifaciens, a viral enhancer element, and a selectable marker gene (Weigel et al, 2000). When the T-DNA inserts into the genome of transformed plants, the enhancer element can cause up-regulation genes in the vicinity, generally within about 10 kilobase (kb) of the enhancers. To identify transgenic plants, T1 plants were exposed to the selective agent in order to specifically recover transformed plants that expressed the selectable marker and therefore harboring the T-DNA. T2 seed was harvested from these plants. Lipids were extracted from of about 15-20 T2 seeds. Gas chromatography (GC) analysis was performed to determine fatty acid content and composition of seed samples.

An Arabidopsis line that showed a high-oil phenotype was identified, wherein oil content (i.e., fatty acids) constituted about 36.3% of seed mass compared to an average oil content of about 27.0% for seed from other plants grown and analyzed at the same time (a 34% in oil). The association of the HIO32.2 gene with the high oil phenotype was discovered by identifying the site of T-DNA insertion, and as shown in the Examples, demonstrating genetic co-segregation of the high seed oil phenotype and the presence of the T-DNA. Accordingly, HIO32.2 genes and/or polypeptides may be employed in the development of genetically modified plants having a modified oil content phenotype (“a HIO32.2 phenotype”). HIO32.2 genes may be used in the generation of oilseed crops that provide improved oil yield from oilseed processing and in the generation of feed grain crops that provide increased energy for animal feeding. HIO32.2 genes may further be used to increase the oil content of specialty oil crops, in order to augment yield of desired unusual fatty acids. Transgenic plants that have been genetically modified to express HIO32.2 can be used in the production of oil, wherein the transgenic plants are grown, and oil is obtained from plant parts (e.g. seed) using standard methods.

HIO32.2 Nucleic Acids and Polypeptides

Arabidopsis HIO32.2 nucleic acid (genomic DNA) sequence is provided in SEQ ID NO: 1 and in Genbank entry GI#22331644. The corresponding protein sequence is provided in SEQ ID NO:2 and in GI#22331645. Nucleic acids and/or proteins that are orthologs or paralogs of Arabidopsis HIO32.2, are described in Example 3 below.

As used herein, the term “HIO32.2 polypeptide” refers to a full-length HIO32.2 protein or a fragment, derivative (variant), or ortholog thereof that is “functionally active,” meaning that the protein fragment, derivative, or ortholog exhibits one or more or the functional activities associated with the polypeptide of SEQ ID NO:2. In one preferred embodiment, a functionally active HIO32.2 polypeptide causes an altered oil content phenotype when mis-expressed in a plant. In a further preferred embodiment, mis-expression of the HIO32.2 polypeptide causes a high oil phenotype in a plant. In another embodiment, a functionally active HIO32.2 polypeptide is capable of rescuing defective (including deficient) endogenous HIO32.2 activity when expressed in a plant or in plant cells; the rescuing polypeptide may be from the same or from a different species as that with defective activity. In another embodiment, a functionally active fragment of a full length HIO32.2 polypeptide (i.e., a native polypeptide having the sequence of SEQ ID NO:2 or a naturally occurring ortholog thereof) retains one of more of the biological properties associated with the full-length HIO32.2 polypeptide, such as signaling activity, binding activity, catalytic activity, or cellular or extra-cellular localizing activity. A HIO32.2 fragment preferably comprises a HIO32.2 domain, such as a C- or N-terminal or catalytic domain, among others, and preferably comprises at least 10, preferably at least 20, more preferably at least 25, and most preferably at least 50 contiguous amino acids of a HIO32.2 protein. Functional domains can be identified using the PFAM program (Bateman A et al., 1999 Nucleic Acids Res 27:260-262). A preferred HIO32.2 fragment comprises a helix-loop-helix DNA-binding domain (PF00010). Functionally active variants of full-length HIO32.2 polypeptides or fragments thereof include polypeptides with amino acid insertions, deletions, or substitutions that retain one of more of the biological properties associated with the full-length HIO32.2 polypeptide. In some cases, variants are generated that change the post-translational processing of a HIO32.2 polypeptide. For instance, variants may have altered protein transport or protein localization characteristics or altered protein half-life compared to the native polypeptide.

As used herein, the term “HIO32.2 nucleic acid” encompasses nucleic acids with the sequence provided in or complementary to the sequence provided in SEQ ID NO:1, as well as functionally active fragments, derivatives, or orthologs thereof. A HIO32.2 nucleic acid of this invention may be DNA, derived from genomic DNA or cDNA, or RNA.

In one embodiment, a functionally active HIO32.2 nucleic acid encodes or is complementary to a nucleic acid that encodes a functionally active HIO32.2 polypeptide. Included within this definition is genomic DNA that serves as a template for a primary RNA transcript (i.e., an mRNA precursor) that requires processing, such as splicing, before encoding the functionally active HIO32.2 polypeptide. A HIO32.2 nucleic acid can include other non-coding sequences, which may or may not be transcribed; such sequences include 5′ and 3′ UTRs, polyadenylation signals and regulatory sequences that control gene expression, among others, as are known in the art. Some polypeptides require processing events, such as proteolytic cleavage, covalent modification, etc., in order to become fully active. Accordingly, functionally active nucleic acids may encode the mature or the pre-processed HIO32.2 polypeptide, or an intermediate form. A HIO32.2 polynucleotide can also include heterologous coding sequences, for example, sequences that encode a marker included to facilitate the purification of the fused polypeptide, or a transformation marker.

In another embodiment, a functionally active HIO32.2 nucleic acid is capable of being used in the generation of loss-of-function HIO32.2 phenotypes, for instance, via antisense suppression, co-suppression, etc.

In one preferred embodiment, a HIO32.2 nucleic acid used in the methods of this invention comprises a nucleic acid sequence that encodes or is complementary to a sequence that encodes a HIO32.2 polypeptide having at least 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95% or more sequence identity to the polypeptide sequence presented in SEQ ID NO:2.

In another embodiment a HIO32.2 polypeptide of the invention comprises a polypeptide sequence with at least 50% or 60% identity to the HIO32.2 polypeptide sequence of SEQ ID NO:2, and may have at least 70%, 80%, 85%, 90% or 95% or more sequence identity to the HIO32.2 polypeptide sequence of SEQ ID NO:2. In another embodiment, a HIO32.2 polypeptide comprises a polypeptide sequence with at least 50%, 60%, 70%, 80%, 85%, 90% or 95% or more sequence identity to a functionally active fragment of the polypeptide presented in SEQ ID NO:2, such as a helix-loop-helix DNA-binding domain. In yet another embodiment, a HIO32.2 polypeptide comprises a polypeptide sequence with at least 50%, 60%, 70%, 80%, or 90% identity to the polypeptide sequence of SEQ ID NO:2 over its entire length and comprises a helix-loop-helix DNA-binding domain.

In another aspect, a HIO32.2 polynucleotide sequence is at least 50% to 60% identical over its entire length to the HIO32.2 nucleic acid sequence presented as SEQ ID NO: 1, or nucleic acid sequences that are complementary to such a HIO32.2 sequence, and may comprise at least 70%, 80%, 85%, 90% or 95% or more sequence identity to the HIO32.2 sequence presented as SEQ ID NO: 1 or a functionally active fragment thereof, or complementary sequences.

As used herein, “percent (%) sequence identity” with respect to a specified subject sequence, or a specified portion thereof, is defined as the percentage of nucleotides or amino acids in the candidate derivative sequence identical with the nucleotides or amino acids in the subject sequence (or specified portion thereof), after aligning the sequences and introducing gaps, if necessary to achieve the maximum percent sequence identity, as generated by the program WU-BLAST-2.0a19 (Altschul et al., J. Mol. Biol. (1990) 215:403-410) with search parameters set to default values. The HSP S and HSP S2 parameters are dynamic values and are established by the program itself depending upon the composition of the particular sequence and composition of the particular database against which the sequence of interest is being searched. A “% identity value” is determined by the number of matching identical nucleotides or amino acids divided by the sequence length for which the percent identity is being reported. “Percent (%) amino acid sequence similarity” is determined by doing the same calculation as for determining % amino acid sequence identity, but including conservative amino acid substitutions in addition to identical amino acids in the computation. A conservative amino acid substitution is one in which an amino acid is substituted for another amino acid having similar properties such that the folding or activity of the protein is not significantly affected. Aromatic amino acids that can be substituted for each other are phenylalanine, tryptophan, and tyrosine; interchangeable hydrophobic amino acids are leucine, isoleucine, methionine, and valine; interchangeable polar amino acids are glutamine and asparagine; interchangeable basic amino acids are arginine, lysine and histidine; interchangeable acidic amino acids are aspartic acid and glutamic acid; and interchangeable small amino acids are alanine, serine, threonine, cysteine and glycine.

Derivative nucleic acid molecules of the subject nucleic acid molecules include sequences that selectively hybridize to the nucleic acid sequence of SEQ ID NO:1. The stringency of hybridization can be controlled by temperature, ionic strength, pH, and the presence of denaturing agents such as formamide during hybridization and washing. Conditions routinely used are well known (see, e.g., Current Protocol in Molecular Biology, Vol. 1, Chap. 2.10, John Wiley & Sons, Publishers (1994); Sambrook et al., Molecular Cloning, Cold Spring Harbor (1989)). In some embodiments, a nucleic acid molecule of the invention is capable of hybridizing to a nucleic acid molecule containing the nucleotide sequence of SEQ ID NO:1 under stringent hybridization conditions that are: prehybridization of filters containing nucleic acid for 8 hours to overnight at 65° C. in a solution comprising 6× single strength citrate (SSC) (1×SSC is 0.15 M NaCl, 0.015 M Na citrate; pH 7.0), 5× Denhardt's solution, 0.05% sodium pyrophosphate and 100 μg/ml herring sperm DNA; hybridization for 18-20 hours at 65° C. in a solution containing 6×SSC, 1× Denhardt's solution, 100 μg/ml yeast tRNA and 0.05% sodium pyrophosphate; and washing of filters at 65° C. for 1 h in a solution containing 0.1×SSC and 0.1% SDS (sodium dodecyl sulfate). In other embodiments, moderately stringent hybridization conditions are used that are: pretreatment of filters containing nucleic acid for 6 h at 40° C. in a solution containing 35% formamide, 5×SSC, 50 mM Tris-HCl (pH 7.5), 5 mM EDTA, 0.1% PVP, 0.1% Ficoll, 1% BSA, and 500 μg/ml denatured salmon sperm DNA; hybridization for 18-20 h at 40° C. in a solution containing 35% formamide, 5×SSC, 50 mM Tris-HCl (pH 7.5), 5 mM EDTA, 0.02% PVP, 0.02% Ficoll, 0.2% BSA, 100 μg/ml salmon sperm DNA, and 10% (wt/vol) dextran sulfate; followed by washing twice for 1 hour at 55° C. in a solution containing 2×SSC and 0.1% SDS. Alternatively, low stringency conditions can be used that comprise: incubation for 8 hours to overnight at 37° C. in a solution comprising 20% formamide, 5×SSC, 50 mM sodium phosphate (pH 7.6), 5× Denhardt's solution, 10% dextran sulfate, and 20 μg/ml denatured sheared salmon sperm DNA; hybridization in the same buffer for 18 to 20 hours; and washing of filters in 1×SSC at about 37° C. for 1 hour.

As a result of the degeneracy of the genetic code, a number of polynucleotide sequences encoding a HIO32.2 polypeptide can be produced. For example, codons may be selected to increase the rate at which expression of the polypeptide occurs in a particular host species, in accordance with the optimum codon usage dictated by the particular host organism (see, e.g., Nakamura et al, 1999). Such sequence variants may be used in the methods of this invention.

The methods of the invention may use orthologs of the Arabidopsis HIO32.2. Methods of identifying the orthologs in other plant species are known in the art. Normally, orthologs in different species retain the same function, due to presence of one or more protein motifs and/or 3-dimensional structures. In evolution, when a gene duplication event follows speciation, a single gene in one species, such as Arabidopsis, may correspond to multiple genes (paralogs) in another. As used herein, the term “orthologs” encompasses paralogs. When sequence data is available for a particular plant species, orthologs are generally identified by sequence homology analysis, such as BLAST analysis, usually using protein bait sequences. Sequences are assigned as a potential ortholog if the best hit sequence from the forward BLAST result retrieves the original query sequence in the reverse BLAST (Huynen M A and Bork P, Proc Natl Acad Sci (1998) 95:5849-5856; Huynen M A et al., Genome Research (2000) 10:1204-1210). Programs for multiple sequence alignment, such as CLUSTAL (Thompson J D et al, 1994, Nucleic Acids Res 22:4673-4680) may be used to highlight conserved regions and/or residues of orthologous proteins and to generate phylogenetic trees. In a phylogenetic tree representing multiple homologous sequences from diverse species (e.g., retrieved through BLAST analysis), orthologous sequences from two species generally appear closest on the tree with respect to all other sequences from these two species. Structural threading or other analysis of protein folding (e.g., using software by ProCeryon, Biosciences, Salzburg, Austria) may also identify potential orthologs. Nucleic acid hybridization methods may also be used to find orthologous genes and are preferred when sequence data are not available. Degenerate PCR and screening of cDNA or genomic DNA libraries are common methods for finding related gene sequences and are well known in the art (see, e.g., Sambrook, 1989; Dieffenbach and Dveksler, 1995). For instance, methods for generating a cDNA library from the plant species of interest and probing the library with partially homologous gene probes are described in Sambrook et al. A highly conserved portion of the Arabidopsis HIO32.2 coding sequence may be used as a probe. HIO32.2 ortholog nucleic acids may hybridize to the nucleic acid of SEQ ID NO:1 under high, moderate, or low stringency conditions. After amplification or isolation of a segment of a putative ortholog, that segment may be cloned and sequenced by standard techniques and utilized as a probe to isolate a complete cDNA or genomic clone. Alternatively, it is possible to initiate an EST project to generate a database of sequence information for the plant species of interest. In another approach, antibodies that specifically bind known HIO32.2 polypeptides are used for ortholog isolation (see, e.g., Harlow and Lane, 1988, 1999). Western blot analysis can determine that a HIO32.2 ortholog (i.e., an orthologous protein) is present in a crude extract of a particular plant species. When reactivity is observed, the sequence encoding the candidate ortholog may be isolated by screening expression libraries representing the particular plant species. Expression libraries can be constructed in a variety of commercially available vectors, including lambda gt11, as described in Sambrook, et al., 1989. Once the candidate ortholog(s) are identified by any of these means, candidate orthologous sequence are used as bait (the “query”) for the reverse BLAST against sequences from Arabidopsis or other species in which HIO32.2 nucleic acid and/or polypeptide sequences have been identified.

HIO32.2 nucleic acids and polypeptides may be obtained using any available method. For instance, techniques for isolating cDNA or genomic DNA sequences of interest by screening DNA libraries or by using polymerase chain reaction (PCR), as previously described, are well known in the art. Alternatively, nucleic acid sequence may be synthesized. Any known method, such as site directed mutagenesis (Kunkel T A et al., 1991), may be used to introduce desired changes into a cloned nucleic acid.

In general, the methods of the invention involve incorporating the desired form of the HIO32.2 nucleic acid into a plant expression vector for transformation of in plant cells, and the HIO32.2 polypeptide is expressed in the host plant.

An isolated HIO32.2 nucleic acid molecule is other than in the form or setting in which it is found in nature and is identified and separated from least one contaminant nucleic acid molecule with which it is ordinarily associated in the natural source of the HIO32.2 nucleic acid. However, an isolated HIO32.2 nucleic acid molecule includes HIO32.2 nucleic acid molecules contained in cells that ordinarily express HIO32.2 where, for example, the nucleic acid molecule is in a chromosomal location different from that of natural cells.

Generation of Genetically Modified Plants with an Altered Oil Content Phenotype

HIO32.2 nucleic acids and polypeptides may be used in the generation of genetically modified plants having a modified oil content phenotype. As used herein, a “modified oil content phenotype” may refer to modified oil content in any part of the plant; the modified oil content is often observed in seeds. In a preferred embodiment, altered expression of the HIO32.2 gene in a plant is used to generate plants with a high oil phenotype.

The methods described herein are generally applicable to all plants. Although activation tagging and gene identification is carried out in Arabidopsis, the HIO32.2 gene (or an ortholog, variant or fragment thereof) may be expressed in any type of plant. In a preferred embodiment, the invention is directed to oil-producing plants, which produce and store triacylglycerol in specific organs, primarily in seeds. Such species include soybean (Glycine max), rapeseed and canola (including Brassica napus, B. campestris), sunflower (Helianttius annus), cotton (Gossypiuyn hirsutum), corn (Zea mays), cocoa (Theobroma cacao), safflower (Carthamus tinctorius), oil palm (Elaeis guineensis), coconut palm (Cocos nucifera), flax (Linum usitatissimum), castor (Ricinus communis) and peanut (Arachis hypogaea). The invention may also be directed to fruit- and vegetable-bearing plants, grain-producing plants, nut-producing plants, rapid cycling Brassica species, alfalfa (Medicago sativa), tobacco (Nicotiana), turfgrass (Poaceae family), other forage crops, and wild species that may be a source of unique fatty acids.

The skilled artisan will recognize that a wide variety of transformation techniques exist in the art, and new techniques are continually becoming available. Any technique that is suitable for the target host plant can be employed within the scope of the present invention. For example, the constructs can be introduced in a variety of forms including, but not limited to as a strand of DNA, in a plasmid, or in an artificial chromosome. The introduction of the constructs into the target plant cells can be accomplished by a variety of techniques, including, but not limited to Agrobacterium-mediated transformation, electroporation, microinjection, microprojectile bombardment calcium-phosphate-DNA co-precipitation or liposome-mediated transformation of a heterologous nucleic acid. The transformation of the plant is preferably permanent, i.e. by integration of the introduced expression constructs into the host plant genome, so that the introduced constructs are passed onto successive plant generations. Depending upon the intended use, a heterologous nucleic acid construct comprising an HIO32.2 polynucleotide may encode the entire protein or a biologically active portion thereof.

In one embodiment, binary Ti-based vector systems may be used to transfer polynucleotides. Standard Agrobacterium binary vectors are known to those of skill in the art, and many are commercially available (e.g., pBI121 Clontech Laboratories, Palo Alto, Calif.).

The optimal procedure for transformation of plants with Agrobacterium vectors will vary with the type of plant being transformed. Exemplary methods for Agrobacterium-mediated transformation include transformation of explants of hypocotyl, shoot tip, stem or leaf tissue, derived from sterile seedlings and/or plantlets. Such transformed plants may be reproduced sexually, or by cell or tissue culture. Agrobacterium transformation has been previously described for a large number of different types of plants and methods for such transformation may be found in the scientific literature. Of particular relevance are methods to transform commercially important crops, such as rapeseed (De Block et al., 1989), sunflower (Everett et al., 1987), and soybean (Christou et al., 1989; Kline et al., 1987).

Expression (including transcription and translation) of HIO32.2 may be regulated with respect to the level of expression, the tissue type(s) where expression takes place and/or developmental stage of expression. A number of heterologous regulatory sequences (e.g., promoters and enhancers) are available for controlling the expression of a HIO32.2 nucleic acid. These include constitutive, inducible and regulatable promoters, as well as promoters and enhancers that control expression in a tissue- or temporal-specific manner. Exemplary constitutive promoters include the raspberry E4 promoter (U.S. Pat. Nos. 5,783,393 and 5,783,394), the 35S CaMV (Jones J D et al, 1992), the CsVMV promoter (Verdaguer B et al., 1998) and the melon actin promoter (published PCT application WO0056863). Exemplary tissue-specific promoters include the tomato E4 and E8 promoters (U.S. Pat. No. 5,859,330) and the tomato 2AII gene promoter (Van Haaren M J J et al., 1993).

In one preferred embodiment, HIO32.2 expression is under control of regulatory sequences from genes whose expression is associated with early seed and/or embryo development. Legume genes whose promoters are associated with early seed and embryo development include V. faba legunzin (Baumlein et al., 1991, Mol Gen Genet 225:121-8; Baumlein et al., 1992, Plant J 2:233-9), V. faba usp (Fiedler et al., 1993, Plant Mol Biol 22:669-79), pea convicilin (Bown et al., 1988, Biochem J 251:717-26), pea lectin (dePater et al., 1993, Plant Cell 5:877-86), P. vulgaris beta phaseolin (Bustos et al., 1991, EMBO J 10:1469-79), P. vulgaris DLEC2 and PHS [beta] (Bobb et al, 1997, Nucleic Acids Res 25:641-7), and soybean beta-Conglycinin, 7S storage protein (Chamberland et al., 1992, Plant Mol Biol 19:937-49). Cereal genes whose promoters are associated with early seed and embryo development include rice glutelin (“GluA-3,” Yoshihara and Takaiwa, 1996, Plant Cell Physiol 37:107-11; “GluB-1,” Takaiwa et al., 1996, Plant Mol Biol 30:1207-21; Washida et al., 1999, Plant Mol Biol 40:1-12; “Gt3,” Leisy et al., 1990, Plant Mol Biol 14:41-50), rice prolamin (Zhou & Fan, 1993, Transgenic Res 2:141-6), wheat prolamin (Hammond-Kosack et al., 1993, EMBO J 12:545-54), maize zein (Z4, Matzke et al., 1990, Plant Mol Biol 14:323-32), and barley B-hordeinis (Entwistle et al., 1991, Plant Mol Biol 117:1217-31). Other genes whose promoters are associated with early seed and embryo development include oil palm GLO7A (7S globulin, Morcillo et al., 2001, Physiol Plant 112:233-243), Brassica napus napin, 2S storage protein, and napA gene (Josefsson et al., 1987, J Biol Chem 262:12196-201; Stalberg et al., 1993, Plant Mol Biol 1993 23:671-83; Ellerstrom et al., 1996, Plant Mol Biol 32:1019-27), Brassica napus oleosin (Keddie et al., 1994, Plant Mol Biol 24:327-40), Arabidopsis oleosin (Plant et al., 1994, Plant Mol Biol 25:193-205), Arabidopsis FAE1 (Rossak et al., 2001, Plant Mol Biol 46:717-25), Canavalia gladiata conA (Yamamoto et al., 1995, Plant Mol Biol 27:729-41), and Catharanthus roseus strictosidine synthase (Str, Ouwerkerk and Memelink, 1999, Mol Gen Genet 261:635-43). In another preferred embodiment, regulatory sequences from genes expressed during oil biosynthesis are used (see, e.g., U.S. Pat. No. 5,952,544). Alternative promoters are from plant storage protein genes (Bevan et al, 1993, Philos Trans R Soc Lond B Biol Sci 342:209-15).

In yet another aspect, in some cases it may be desirable to inhibit the expression of endogenous HIO32.2 in a host cell. Exemplary methods for practicing this aspect of the invention include, but are not limited to antisense suppression (Smith, et al., 1988; van der Krol et al., 1988); co-suppression (Napoli, et al., 1990); ribozymes (PCT Publication WO 97/10328); and combinations of sense and antisense (Waterhouse, et al., 1998). Methods for the suppression of endogenous sequences in a host cell typically employ the transcription or transcription and translation of at least a portion of the sequence to be suppressed. Such sequences may be homologous to coding as well as non-coding regions of the endogenous sequence. Antisense inhibition may use the entire cDNA sequence (Sheehy et al., 1988), a partial cDNA sequence including fragments of 5′ coding sequence, (Cannon et al., 1990), or 3′ non-coding sequences (Ch'ng et al., 1989). Cosuppression techniques may use the entire cDNA sequence (Napoli et al., 1990; van der Krol et al., 1990), or a partial cDNA sequence (Smith et al., (1990).

Standard molecular and genetic tests may be performed to further analyze the association between a gene and an observed phenotype. Exemplary techniques are described below.

1. DNA/RNA Analysis

The stage- and tissue-specific gene expression patterns in mutant versus wild-type lines may be determined, for instance, by in situ hybridization. Analysis of the methylation status of the gene, especially flanking regulatory regions, may be performed. Other suitable techniques include overexpression, ectopic expression, expression in other plant species and gene knock-out (reverse genetics, targeted knock-out, viral induced gene silencing [VIGS, see Baulcombe D, 1999]).

In a preferred application expression profiling, generally by microarray analysis, is used to simultaneously measure differences or induced changes in the expression of many different genes. Techniques for microarray analysis are well known in the art (Schena M et al., Science (1995) 270:467-470; Baldwin D et al., 1999; Dangond F, Physiol Genomics (2000) 2:53-58; van Hal N L et al., J Biotechnol (2000) 78:271-280; Richmond T and Somerville S, Curr Opin Plant Biol (2000) 3:108-116). Expression profiling of individual tagged lines may be performed. Such analysis can identify other genes that are coordinately regulated as a consequence of the overexpression of the gene of interest, which may help to place an unknown gene in a particular pathway.

2. Gene Product Analysis

Analysis of gene products may include recombinant protein expression, antisera production, immunolocalization, biochemical assays for catalytic or other activity, analysis of phosphorylation status, and analysis of interaction with other proteins via yeast two-hybrid assays.

3. Pathway Analysis

Pathway analysis may include placing a gene or gene product within a particular biochemical, metabolic or signaling pathway based on its mis-expression phenotype or by sequence homology with related genes. Alternatively, analysis may comprise genetic crosses with wild-type lines and other mutant lines (creating double mutants) to order the gene in a pathway, or determining the effect of a mutation on expression of downstream “eporter” genes in a pathway.

Generation of Mutated Plants with an Altered Oil Content Phenotype

The invention further provides a method of identifying non-transgenic plants that have mutations in or an allele of endogenous HIO32.3 that confer a HIO32.3 phenotype to these plants and their progeny. In one method, called “TILLING” (for targeting induced local lesions in genomes), mutations are induced in the seed of a plant of interest, for example, using EMS treatment. The resulting plants are grown and self-fertilized, and the progeny are used to prepare DNA samples. HIO32.3-specific PCR is used to identify whether a mutated plant has a HIO32.3 mutation. Plants having HIO32.3 mutations may then be tested for altered oil content, or alternatively, plants may be tested for altered oil content, and then HIO32.3-specific PCR is used to determine whether a plant having altered oil content has a mutated HIO32.3 gene. TILLING can identify mutations that may alter the expression of specific genes or the activity of proteins encoded by these genes (see Colbert et al (2001) Plant Physiol 126:480-484; McCallum et al (2000) Nature Biotechnology 18:455-457).

In another method, a candidate gene Quantitative Trait Locus (QTLs) approach can be used in a marker-assisted breeding program to identify alleles of or mutations in the HIO32.3 gene or orthologs of HIO32.3 that may confer altered oil content (see Bert et al., Theor Appl Genet. 2003 June; 107(1):181-9; and Lionneton, et al, Genome. 2002 December; 45(6):1203-15). Thus, in a further aspect of the invention, a HIO32.3 nucleic acid is used to identify whether a plant having altered oil content has a mutation in endogenous HIO32.3 or has a particular allele that causes altered oil content.

While the invention has been described with reference to specific methods and embodiments, it will be appreciated that various modifications and changes may be made without departing from the invention. All publications cited herein are expressly incorporated herein by reference for the purpose of describing and disclosing compositions and methodologies that might be used in connection with the invention. All cited patents, patent applications, and sequence information in referenced public databases are also incorporated by reference.

EXAMPLES Example 1

Generation of Plants with a HIO32.2 Phenotype by Transformation with an Activation Tagging Construct

Mutants were generated using the activation tagging “ACTTAG” vector, pSKI015 (GI#6537289; Weigel D et al., 2000). Standard methods were used for the generation of Arabidopsis transgenic plants, and were essentially as described in published application PCT WO0183697. Briefly, T0 Arabidopsis (Col-0) plants were transformed with Agrobacterium carrying the pSKI015 vector, which comprises T-DNA derived from the Agrobacterium Ti plasmid, an herbicide resistance selectable marker gene, and the 4× CaMV 35S enhancer element. Transgenic plants were selected at the T1 generation based on herbicide resistance. T2 seed was collected from T1 plants and stored in an indexed collection, and a portion of the T2 seed was accessed for the screen.

Quantitative determination of seed fatty acid content was performed using the following methods. A sample of 15 to 20 T2 seeds from each line tested, which generally contained homozygous insertion, homozygous wild-type, and heterozygous genotypes in a standard 1:1:2 ratio, was massed on UMT-2 ultra-microbalance (Mettler-Toledo Co., Ohio, USA) and then transferred to a glass extraction vial. Lipids were extracted from the seeds and trans-esterified in 500 ul 2.5% H₂SO₄ in MeOH for 3 hours at 80° C., following the method of Browse et al. (Biochem J 235:25-31, 1986) with modifications. A known amount of heptadecanoic acid was included in the reaction as an internal standard. 750 ul of water and 400 ul of hexane were added to each vial, which was then shaken vigorously and allowed to phase separate. Reaction vials were loaded directly onto GC for analysis and the upper hexane phase was sampled by the autosampler. Gas chromatography with Flame Ionization detection was used to separate and quantify the fatty acid methyl esters. Agilent 6890 Plus GC's were used for separation with Agilent Innowax columns (30 m×0.25 mm ID, 250 um film thickness). The carrier gas was Hydrogen at a constant flow of 2.5 ml/minute. 1 ul of sample was injected in splitless mode (inlet temperature 220° C., Purge flow 15 ml/min at 1 minute). The oven was programmed for an initial temperature of 105° C., initial time 0.5 minutes, followed by a ramp of 60° C. per minute to 175° C., a 40° C./minute ramp to 260° C. with a final hold time of 2 minutes. Detection was by Flame Ionization (Temperature 275° C., Fuel flow 30.0 ml/min, Oxidizer 400.0 ml/min). Instrument control and data collection and analysis were monitored using the Millennium Chromatography Management System (Version 3.2, Waters Corporation, Milford, Mass.). Integration and quantification were performed automatically, but all analyses were subsequently examined manually to verify correct peak identification and acceptable signal to noise ratio before inclusion of the derived results in the study.

The ACTTAG line designated WO00082263 was identified as having a high oil phenotype. Specifically, oil constituted 36.3% of seed mass (w/w) compared to an average oil content of 27.0% of other ACTTAG lines grown and analyzed in the same conditions (e.g., reference lines). Reanalysis of the same seed was performed in duplicate. This analysis confirmed an increase in oil content relative to controls. It was concluded that the presence of the ACTTAG locus can increase seed oil content between 7% and 11% relative to controls. It is determined that the high oil phenotype is dominant based on oil content of seeds from genotyped individuals.

Example 2

Characterization of the T-DNA Insertion in Plants Exhibiting the Altered Oil Content Phenotype.

We performed standard molecular analyses, essentially as described in patent application PCT WO0183697, to determine the site of the T-DNA insertion associated with the altered oil content phenotype. Briefly, genomic DNA was extracted from plants exhibiting the altered oil content phenotype. PCR, using primers specific to the pSKI015 vector, confirmed the presence of the 35S enhancer in plants from line WO00082263, and Southern blot analysis verified the genomic integration of the ACTTAG T-DNA and showed the presence of a single T-DNA insertion in the transgenic line.

Plasmid rescue was used to recover genomic DNA flanking the T-DNA insertion, which was then subjected to sequence analysis using a basic BLASTN search and/or a search of the Arabidopsis Information Resource (TAIR) database (publicly available at the Arabidopsis Information Resource website). There was sequence identity to BAC clone T23J7 (GI#4741184), chromosome 3. Sequences from nucleotides 16030-16423 and 16443-17200 were recovered, placing the left border junction upstream of nucleotide 16423 (GI#4741184) and downstream of nucleotide 15443. The sequences from nucleotides 15424-16442 of BAC clone T23J7, chromosome 3 (GI#4741184) are deleted in the mutant chromosome.

To determine whether the T-DNA insertion causes the high seed oil phenotype co-segregation of the high seed oil phenotype and the presence of the T-DNA was tested. Eighteen T2 plants were grown to maturity and seed harvested from these plants was used to determine the seed oil phenotype. The seed oil content from these was determined as described in Example 1. The genotype of the T2 seed was inferred by analyzing the T3 seed for the presence or absence of the T-DNA at the site of the insertion by PCR using primers that are specific to the corresponding genomic region and the T-DNA. The results show that the average oil content of T3 seed containing the T-DNA insert was higher than those families lacking the insert. T2 individuals homozygous for the T-DNA at this locus produced seed with an oil content of 107.5% compared to progeny lacking the T-DNA. T2 individuals hemizygous for these loci produced seed with an oil content of 112.7% compared to progeny lacking the T-DNA. Because the homozygotes and hemizygotes for the high oil loci display a similar increase in oil content, we conclude that the T-DNA is linked with the high oil phenotype and the phenotype is caused by a dominant mutation.

Sequence analysis revealed that the left border of the T-DNA insert was about 954 base pairs 3′ of the translation start site of the gene whose nucleotide sequence is presented as SEQ ID NO: 1 which we designated HIO32.2.

Example 3

Analysis of Arabidopsis HIO32.2 Sequence

Sequence analyses were performed with BLAST (Altschul et al., 1997, J. Mol. Biol. 215:403-410), PFAM (Bateman et al., 1999, Nucleic Acids Res 27:260-262), PSORT (Nakai K, and Horton P, 1999, Trends Biochem Sci 24:34-6), and/or CLUSTAL (Thompson J D et al, 1994, Nucleic Acids Res 22:4673-4680).

The TAIR prediction of At3g47710 corresponds to amino acid residues 15-92 of Genbank prediction (gi|22331644). In neither cases is the residue immediately follows the translation initiation codon (ATG) a guanosine (G), which is typical for most genes in Arabidopsis. It is likely that the predicted gene structure for At3g47710 has an atypical residue (thymidine, T) following the translation initiation codon (ATG). This proposal is supported by the fact that three Arabidopsis homologues of At3g47710 (At1g74500, At5g39860 and gi|21617952) whose gene structures are supported by cDNAs have the sequence ATGT at the initiation codons.

BLASTN Against ESTs:

No Arabidopsis EST shows exact match to the candidate gene At3g47710. However, ESTs corresponding to Arabidopsis homologues of At3g47710 can be identified. These genes are described in the BLASTP analysis below.

There are also other similar plant ESTs showing similarity to At3g47700. If possible, ESTs contigs of each species were made. The best hit for each of the following species are listed below and included in the “Orthologue Table” below: Glycine max, Lycopersicon esculentun, Gossypium arboreum, Zea mays, Oryza sativa, Triticum aestivum, Solanum tuberosum.

1. One EST contig from soybean (Glycine max) >gi|16344264|gb|BI969859.1|BI969859 GM830009A23D05 >gi|16344265|gb|BI969860.1|BI969860 GM830009A23D06 >gi|10848131|gb|BF070679.1|BF070679 st23h10.y1 >gi|19345905|gb|BM890785.1|BM890785 sam07g12.y1 >gi|7925404|gb|AW831369.1|AW831369 sm24d03.y1 Score = 310 (114.2 bits), Expect = 2.8e−33

These ESTs were isolated from mixed tissues of various developmental stages or from germinating shoots.

The contigged sequence is presented as SEQ ID NO:3 below.

2. One EST from wheat (Triticum aestivum) >gi|20103472|dbj|BJ282051.1|BJ282051 BJ282051 from an unpublished cDNA library. Score = 286 (105.7 bits), Expect = 9.9e−31 The EST described above (gi|20103472) encompasses the following EST >gi|20106345|dbj|BJ287183.1|BJ287183 BJ287183 from an unpublished cDNA library. 3. One EST from tomato (Lycopersicon esculentum) >gi|7409117|gb|AW647879.1|AW647879 EST326333 tomato germinating seedlings, TAMU library Score = 278 (102.9 bits), Expect = 6.9e−30 4. One EST from potato (Solatium tuberosum) >gi|21375581|gb|BQ516712.1|BQ516712 EST624127 from a library constructed with mixed tomato tissues Score = 265 (98.3 bits), Expect = 1.7e−28 The EST described above (gi|20103472) encompasses the following EST >gi|21375582|gb|BQ516713.1|BQ516713 EST624128 from a library constructed with mixed tomato tissues 5. One EST from rice (Oryza sativa) >gi|8334893|gb|BE039877.1|BE039877 OC09D12 OC Oryza sativa cDNA 5′, mRNA from 1 week old roots Score = 228 (85.3 bits), Expect = 1.4e−24 6. One EST from maize (Zea mays) >gi|18173123|gb|BM348511.1|BM348511 MEST292-A06.T3 ISUM5-RN Zea mays cDNA clone isolated from a B73 Maize library constructed with tissues from various stages and treated with a variety of hormones Score = 202 (76.2 bits), Expect = 7.9e−22, 7. One EST from tree cotton (Gossypium arboreum) >gi|18098731|gb|BM357985.1|BM357985 GA_Ea0003E23r Gossypium arboreum 7-10 dpa fiber library Score = 197 (74.4 bits), Expect = 2.7e−21 BLASTP Against all.aa Results:

At3g47710 has homology to a small number of plant proteins. The top 7 BLAST hits are listed below and are included in the “Orthologue Table” below.

1. Itself (3 redundant entries) >gi|22331645|ref|NP_190355.2|bHLH protein; protein id: At3g47710.1 [Arabidopsis thaliana] Score = 123 bits (309), Expect = 5e−28 The following 2 sequences are redundant entries of At3g47710 based on Genbank annotation. The predicted gene structure for At3g47710 from gi|7487374 and gi|4741188 corresponds to amino acid residues 15-92 of gi|22331645. >gi|7487374|pir||T07710 hypothetical protein T23J7.40 - Arabidopsis thaliana >gi|4741188|emb|CAB41854.1|hypothetical protein [Arabidopsis thaliana] Score = 111 bits (277), Expect = 2e−24 2. At1g74500 from Arabidopsis (4 redundant entries) >gi|15221264|ref|NP_177590.1|bHLH protein; protein id: At1g74500.1, supported by cDNA: 519. [Arabidopsis thaliana] >gi|25406349|pir||A96774 probable DNA-binding protein F1M20.18 [imported] - Arabidopsis thaliana >gi|12324788|gb|AAG52350.1|AC011765_2 putative DNA-binding protein; 54988-54618 [Arabidopsis thaliana] >gi|21593858|gb|AAM65825.1|putative DNA-binding protein [Arabidopsis thaliana] Score = 78.2 bits (191), Expect = 2e−14 3. A DNA-binding protein-like protein from chromosome 3 of Arabidopsis (2 redundant entries in Genbank) >gi|21617952|gb|AAM67002.1|DNA-binding protein-like [Arabidopsis thaliana] Score = 73.9 bits (180), Expect = 4e−13 This is a gene represented by a cDNA that is mapped to chromosome 3 of Arabidopsis. There is no TAIR annotation of this gene. The following entry is likely to be a redundant entry of gi|21617952, because BLASTN shows that the sequences gi|21617952 and gi|9294226 are localized to the same place in the Arabidopsis genome. The sequences gi|21617952 and gi|9294226 differ by a few amino acids. These are likely to be sequencing errors or single nucleotide polymorphisms with little or no effect on activity. >gi|9294226|dbj|BAB02128.1|DNA-binding protein-like [Arabidopsis thaliana] Score = 74.7 bits (182), Expect = 2e−13 4. At5g39860 of Arabidopsis (3 redundant entries in Genbank) >gi|15242499|ref|NP_198802.1|bHLH protein; protein id: At5g39860.1 [Arabidopsis thaliana] >gi|10176978|dbj|BAB10210.1|DNA-binding protein-like [Arabidopsis thaliana] >gi|21593819|gb|AAM65786.1|DNA-binding protein-like [Arabidopsis thaliana] Score = 70.9 bits (172), Expect = 4e−12 5. At5g15160 of Arabidopsis (3 redundant entries in Genbank) >gi|15242227)ref|NP_197020.1|bHLH protein; protein id: At5g15160.1 [Arabidopsis thaliana] >gi|11357892|pir||T49951 hypothetical protein F8M21.50 - Arabidopsis thaliana >gi|7671485|emb|CAB89326.1|putative protein [Arabidopsis thaliana] Score = 69.7 bits (169), Expect = 8e−12 6. A hypothetical protein from rice (Oryza sativa) >gi|21671920|gb|AAM74282.1|AC083943_22 Hypothetical protein similar to putative DNA binding proteins [Oryza sativa (japonica cultivar-group)] Score = 54.3 bits (129), Expect = 4e−07 7. A putative protein from rice (Oryza sativa) >gi|10241623|emb|CAC09463.1|putative DNA binding protein [Oryza sativa (indica cultivar-group)] Score = 53.5 bits (127), Expect = 6e−07

% ID to NEWGENE Score(s) motif or to Ortholog % ID to (BLAST, Coordinates Pfam/other Gene Name Species GI # HIO32.2 Clustal, etc.) of protein motif(s) consensus A hypothetical Oryza sativa >gi|21671920 Length = 88 BLASTP Score = SM00353: aa 4-56 SM00353: protein from (japonica Identities = 54.3 bits (129), Score = −0.5, rice cultivar-group) 44/93 (47%), Expect = 4e−07 E value = 0.13 Positives = PF00010: aa 5-61 PF00010: 65/93 (69%) Score = 11.4, E value = 0.0018 A putative Oryza sativa >gi|10241623 Length = 104 BLASTP Score = SM00353: aa 26-77 SM00353: protein from (indica Identities = 53.5 bits (127), Score = 13.7, rice cultivar-group) 53/102 (51%), Expect = 6e−07 E value = 0.0097 Positives = PF00010: aa 23-72 PF00010: 70/102 (68%) Score = 7.9, E value = 0.017 An EST Glycine max >gi|16344264 Partial sequence, BLASTN Score = SM00353: aa 18-73 SM00353: contig from >gi|16344265 using reading 310 (114.2 bits), Score = 16.2, soybean >gi|10848131 frame + 1 Expect = 2.8e−33, E value = 0.0049 >gi|19345905 Length = 99 P = 2.8e−33 PF00010: aa 18-68 PF00010: >gi|7925404 Identities = Score = 11.0, 66/93 (70%), E value = 0.0076 Positives = 83/93 (89%) A wheat Triticum >gi|20103472 Partial sequence, BLASTN Score = SM00353: aa 41-90 SM00353: EST aestivum using reading 286 (105.7 bits), Score = 11.1, frame + 3 Expect = 9.9e−31, E value = 0.019 Length = 116 P = 9.9e−31 PF00010: aa 29-85 PF00010: Identities = Score = 0.4, 64/93 (68%), E value = 0.11 Positives = 79/93 (84%) A tomato Triticum >gi|7409117 Partial sequence, BLASTN Score = SM00353: aa 10-64 SM00353: EST aestivum using reading 278 (102.9 bits), Score = 12.6, frame + 2 Expect = 6.9e−30, E value = 0.013 Length = 91 P = 6.9e−30 PF00010: aa 9-59 PF00010: Identities = Score = 6.9, 65/93 (69%), E value = 0.021 Positives = 77/93 (82%) A potato Solanum >gi|21375581 Partial sequence, BLASTN Score = SM00353: aa 16-71 SM00353: EST tuberosum using reading 265 (98.3 bits), Score = 9.1, frame + 1 Expect = 1.7e−28, E value = 0.033 Length = 109 P = 1.7e−28 PF00010: aa 13-66 PF00010: Identities = Score = 1.9, 61/95 (64%), E value = 0.074 Positives = 77/95 (81%) A rice EST Oryza sativa >gi|8334893 Partial sequence, BLASTN Score = SM00353: aa 2-49 SM00353: from root using reading 228 (85.3 bits), Score = 7.9, frame + 2 Expect = 1.4e−24, E value = 0.043 Length = 76 P = 1.4e−24 PF00010: aa 1-44 PF00010: Identities= Score = −1.0, 52/77 (67%), E value = 0.14 Positives = 64/77 (83%) A maize Zea mays >gi|18173123 Partial sequence, BLASTN Score = SM00353: aa 42-94 SM00353: EST using reading 202 (76.2 bits), Score = 12.7, frame − 2 Expect = 7.9e−22, E value = 0.013 Length = 121 P = 7.9e−22 PF00010: aa 37-89 PF00010: Identities = Score = 5.2, 54/104 (51%), E value = 0.032 Positives = 74/104 (71%) A cotton Gossypium >gi|18098731 Partial sequence, BLASTN Score = SM00353: aa 7-58 SM00353: fiber EST arboreum using reading 197 (74.4 bits), Score = 26.3, frame − 2 Expect = 2.7e−21, E value = 7.6e−05 Length = 85 P = 2.7e−21 PF00010: aa 4-53 PF00010: Identities = Score = 14.4, 41/83 (49%), E value = 0.0033 Positives = 62/83 (74%) Closest Arabidopsis homologs: At1g74500 Arabidopsis >gi|15221264 Length = 93 BLASTP Score = SM00353: aa 16-67 SM00353: thaliana >gi|25406349 Identities = 78.2 bits (191), Score = 21.7, >gi|12324788 58/93 (62%), Expect = 2e−14 E value = 0.0011 >gi|21593858 Positives = PF00010: aa 7-62 PF00010: 77/93 (82%) Score = −14.3, E value = 0.033 A DNA- Arabidopsis >gi|21617952 Length = 92 BLASTP Score = SM00353: aa 10-65 SM00353: binding protein- thaliana Identities = 73.9 bits (180), Score = 7.8, like protein 57/93 (61%), Expect = 4e−13 E value = 0.048 Positives = PF00010: aa 6-60 PF00010: 74/93 (79%) Score = −0.9, E value = 0.15 At5g39860 Arabidopsis >gi|15242499 Length = 92 BLASTP Score = SM00353: aa 10-65 SM00353: thaliana >gi|10176978 Identities = 70.9 bits (172), Score = 3.6, >gi|21593819 55/93 (59%), Expect = 4e−12 E value = 0.15 Positives = PF00010: aa 5-60 PF00010: 71/93 (76%) Score = −0.3, E value = 0.13 At5g15160 Arabidopsis >gi|15242227 Length = 94 BLASTP Score = SM00353: aa 6-61 SM00353: thaliana >gi|11357892 Identities = 69.7 bits (169), Score = 4.8, >gi|7671485 53/91 (58%), Expect = 8e−12 E value = 0.036 Positives = PF00010: aa 11-66 PF00010: 71/91 (78%) Score = −9.6, E value = 0.029

At3g47710 is a non-secrtetory protein that lacks transmembrane domain (predicted by TMHMM) and signal peptide (predicted by SignalP). PSORT2 predicts At3g47710 to be localized to the mitochondria (64% mitochondrial, 24% nuclear, 8% cytoplasmic, 4% peroxisomal). However, Predator analysis gives contradictory results and suggests that At3g47710 is localized to neither the mitochondria nor the plastid (5% mitochondrial, 0% plastid). Therefore

Pfam analysis showed that At3g47710 shows weak homology to the helix-loop-helix DNA-binding domain (PF00010, SM00353). The basic helix-loop-helix proteins (bHLH) are a group of eukaryotic transcription factors that have diverse functions. These transcription factors are characterized by a highly conserved bHLH domain that mediates DNA binding and dimerisation with other proteins (Littlewood and Evan, 1995 Protein Profile 2, 621-702).

A number of Arabidopsis bHLH proteins have been characterized and shown to be important for diverse functions such as development of carpel margin, fruit dehiscence, light signal transduction, root hair development and trichome development (Heisler et al., 2001 Development. 128, 1089-1098; Rajani and Sundaresan, 2001, Curr Biol. 11, 1914-1922; Huq and Quail, 2002 EMBO J. 21, 2441-2450; Wada et al., 2002, Development. 129, 5409-5419; Smolen et al., 2002, Genetics. 161, 1235-1246; Sawa, 2002, DNA Res. 9, 31-34). It should be noted that BLASTP analysis of At3g47710 did not identify functionally characterized bHLH proteins in Arabidopsis, suggesting that At3g47710 is a distant family member to these bHLH proteins. Nonetheless, it is conceivable that over-expression of the transcription factor At3g47710 may increase seed oil content by altering expression of downstream genes in either the nucleus or the mitochondria.

Model Domain seq-f seq-t hmm-f hmm-t score E−value SM00353 1/1 16 66 . . . 1 61 [ ] 9.8 0.028 PF00010 1/1 16 61 . . . 1 53 [ ] 1.9 0.073

Example 4

Confirmation of Phenotype/Genotype Association

RT-PCR analysis showed that the HIO32.2 gene was over-expressed in plants from the line displaying the HIO32.2 phenotype. Specifically, RNA was extracted from rosette leaves and/or siliques of plants exhibiting the HIO32.2 phenotype collected at a variety of developmental stages and pooled. RT-PCR was performed using primers specific to the sequence presented as SEQ ID NO:1, to other predicted genes in the vicinity of the T-DNA insertion, and to a constitutively expressed actin gene (positive control). The results showed that in plants displaying the HIO32.2 phenotype, mRNA for the HIO32.2 gene is up-regulated in leaves and down-regulated in siliques.

The dominant inheritance pattern of the HIO32.2 phenotype is confirmed through genetic analysis. In general, genetic analysis involves the production and analysis of F1 hybrids. Typically, F1 crosses are carried out by collecting pollen from T2 plants, which is used to pollinate wild type plants. Such crosses are carried out by taking about 4 flowers from each selected individual plants, and using the T2 flower as the male pollen donor and flowers of the wild type plants as the female. 4-5 crosses are done for an individual of interest. Seed formed from crosses of the same individual are pooled, planted and grown to maturity as F1 hybrids.

Example 5

Recapitulation of the High Oil Phenotype

To confirm whether over-expression of At3g47710 causes a high seed oil phenotype, oil content in seeds from transgenic plants over-expressing this gene was compared with oil content in seeds from non-transgenic control plants. To do this, At3g47710 was cloned into a plant transformation vector behind the strong constitutive CsVMV promoter and transformed into Arabidopsis plants using the floral dip method. The plant transformation vector contains the nptII gene, which provides resistance to kanamyacin, and serves as a selectable marker. Seed from the transformed plants were plated on agar medium containing kanamycin. After 7 days, transgenic plants were identified as healthy green plants and transplanted to soil. Non-transgenic control plants were germinated on agar medium, allowed to grow for 7 days and then transplanted to soil. Twenty-two transgenic seedlings and 10 non-transgenic control plants were transplanted to random positions in the same 32 cell flat. The plants were grown to maturity, allowed to self-fertilize and set seed. Seed was harvested from each plant and its oil content estimated by Near Infrared (NIR) Spectroscopy using methods described below.

NIR infrared spectra were captured using a Bruker 22 N/F near infrared spectrometer. Bruker Software was used to estimate total seed oil and total seed protein content using NIR data from the samples and reference methods according to the manufacturer's instructions. An oil content predicting calibration was developed following the general method of AOCS Procedure Am1-92, Official Methods and Recommended Practices of the American Oil Chemists Society, 5th Ed., AOCS, Champaign Ill). The calibration allowing NIR predictions of Crude Oil Crude Oil ASE (Ren Oil, Accelerated Solvent Extraction) was developed.

The effect of over-expression of At3g47710 on seed oil has been tested in five experiments. In four experiments, the plants over-expressing At3g47710 had higher seed oil content than the control plants grown in the same flat. Across the experiments, the average seed oil content of plants over-expressing At3g47710 was 3.5% greater than the untransformed controls. The in seed oil content in plants over-expressing At3g47710 was significantly greater than non-transgenic control plants (two-way ANOVA; P=0.0066), see Table 1.

TABLE 1 Predicted Relative value Experiment Plant ID Transgene average average 1 DX02948001 CsVMV::HIO32.2 31.2429 93.4123 1 DX02948003 CsVMV::HIO32.2 34.8987 104.3425 1 DX02948004 CsVMV::HIO32.2 32.9915 98.6401 1 DX02948005 CsVMV::HIO32.2 35.0001 104.6456 1 DX02948006 CsVMV::HIO32.2 36.5424 109.2568 1 DX02948007 CsVMV::HIO32.2 36.7931 110.0065 1 DX02948008 CsVMV::HIO32.2 36.4274 108.9132 1 DX02948009 CsVMV::HIO32.2 35.0468 104.7852 1 DX02948011 CsVMV::HIO32.2 34.2905 102.5239 1 DX02948013 CsVMV::HIO32.2 33.4158 99.9088 1 DX02948014 CsVMV::HIO32.2 34.1728 102.1721 1 DX02948015 CsVMV::HIO32.2 31.6579 94.6528 1 DX02947001 None 35.6386 106.5548 1 DX02947002 None 34.0045 101.6688 1 DX02947003 None 32.578 97.4039 1 DX02947004 None 33.5877 100.4227 1 DX02947005 None 33.0303 98.7563 1 DX02947006 None 34.3919 102.8273 1 DX02947007 None 33.1974 99.2558 1 DX02947008 None 31.142 93.1104 2 Z003900001 CsVMV::HIO32.2 33.6896 106.2791 2 Z003900002 CsVMV::HIO32.2 33.3141 105.0947 2 Z003900003 CsVMV::HIO32.2 35.6526 112.4718 2 Z003900004 CsVMV::HIO32.2 27.8247 87.7776 2 Z003900005 CsVMV::HIO32.2 33.1646 104.6231 2 Z003900006 CsVMV::HIO32.2 37.0337 116.8286 2 Z003900008 CsVMV::HIO32.2 34.6903 109.4361 2 Z003900009 CsVMV::HIO32.2 30.981 97.7346 2 Z003900010 CsVMV::HIO32.2 39.056 123.2082 2 Z003900011 CsVMV::HIO32.2 37.1317 117.1378 2 Z003900013 CsVMV::HIO32.2 32.409 102.2392 2 Z003900014 CsVMV::HIO32.2 36.3444 114.6543 2 Z003900015 CsVMV::HIO32.2 36.8128 116.1318 2 Z003900017 CsVMV::HIO32.2 38.4427 121.2736 2 Z003900018 CsVMV::HIO32.2 33.6492 106.1516 2 Z003900020 CsVMV::HIO32.2 30.8397 97.2888 2 Z003900021 CsVMV::HIO32.2 35.9108 113.2864 2 Z003890001 None 36.4237 114.9044 2 Z003890003 None 32.4789 102.4599 2 Z003890004 None 33.9902 107.2273 2 Z003890005 None 29.5647 93.2666 2 Z003890006 None 31.4827 99.3173 2 Z003890007 None 27.8273 87.7857 2 Z003890008 None 26.2013 82.6561 2 Z003890009 None 34.3203 108.269 2 Z003890010 None 33.0031 104.1136 3 Z003978002 CsVMV::HIO32.2 33.4407 97.8939 3 Z003978003 CsVMV::HIO32.2 36.4683 106.7568 3 Z003978004 CsVMV::HIO32.2 34.9617 102.3464 3 Z003978005 CsVMV::HIO32.2 34.7488 101.7233 3 Z003978007 CsVMV::HIO32.2 31.0467 90.8856 3 Z003978008 CsVMV::HIO32.2 36.6832 107.3859 3 Z003978010 CsVMV::HIO32.2 34.8046 101.8866 3 Z003978011 CsVMV::HIO32.2 26.9809 78.9835 3 Z003978012 CsVMV::HIO32.2 32.4106 94.8785 3 Z003978014 CsVMV::HIO32.2 35.5825 104.1638 3 Z003978015 CsVMV::HIO32.2 33.9295 99.3247 3 Z003978016 CsVMV::HIO32.2 34.9754 102.3866 3 Z003978017 CsVMV::HIO32.2 33.5072 98.0887 3 Z003978018 CsVMV::HIO32.2 35.3474 103.4756 3 Z003978019 CsVMV::HIO32.2 33.4171 97.8248 3 Z003978022 CsVMV::HIO32.2 31.2548 91.4948 3 Z003994001 None 35.8594 104.9744 3 Z003994002 None 34.3685 100.61 3 Z003994003 None 34.7967 101.8634 3 Z003994004 None 36.266 106.1646 3 Z003994005 None 30.8633 90.3488 3 Z003994006 None 32.8165 96.0666 3 Z003994007 None 36.5016 106.8543 3 Z003994008 None 34.9869 102.4202 3 Z003994009 None 30.7767 90.0952 3 Z003994010 None 34.3659 100.6024 4 DX06941001 CsVMV::HIO32.2 33.9232 104.5537 4 DX06941002 CsVMV::HIO32.2 33.6401 103.6812 4 DX06941003 CsVMV::HIO32.2 35.7409 110.1562 4 DX06941004 CsVMV::HIO32.2 31.9439 98.4536 4 DX06941005 CsVMV::HIO32.2 31.3507 96.6252 4 DX06941006 CsVMV::HIO32.2 32.5406 100.2926 4 DX06941007 CsVMV::HIO32.2 33.1874 102.286 4 DX06941008 CsVMV::HIO32.2 34.0966 105.0881 4 DX06941009 CsVMV::HIO32.2 34.7597 107.132 4 DX06941010 CsVMV::HIO32.2 32.8897 101.3686 4 DX06941011 CsVMV::HIO32.2 34.0769 105.0275 4 DX06941012 CsVMV::HIO32.2 32.9075 101.4232 4 DX06941013 CsVMV::HIO32.2 36.1765 111.4985 4 DX06941014 CsVMV::HIO32.2 34.3151 105.7617 4 DX06941015 CsVMV::HIO32.2 31.8685 98.2211 4 DX06941016 CsVMV::HIO32.2 32.2279 99.3287 4 DX06941017 CsVMV::HIO32.2 35.2172 108.542 4 DX06941018 CsVMV::HIO32.2 30.4763 93.9302 4 DX06941019 CsVMV::HIO32.2 30.573 94.2281 4 DX06941020 CsVMV::HIO32.2 32.4645 100.0581 4 DX06941021 CsVMV::HIO32.2 36.0598 111.139 4 DX06941022 CsVMV::HIO32.2 31.4834 97.0342 4 DX06959001 None 32.2856 99.5067 4 DX06959002 None 31.1875 96.122 4 DX06959004 None 34.4381 106.1409 4 DX06959005 None 32.1773 99.1728 4 DX06959006 None 33.4702 103.1577 4 DX06959007 None 33.1607 102.2038 4 DX06959008 None 33.1406 102.1416 4 DX06959009 None 29.7743 91.7666 4 DX06959010 None 32.3769 99.7879 5 DX06942001 CsVMV::HIO32.2 32.4339 104.7283 5 DX06942002 CsVMV::HIO32.2 32.5468 105.0928 5 DX06942003 CsVMV::HIO32.2 31.6804 102.2953 5 DX06942004 CsVMV::HIO32.2 31.2728 100.9792 5 DX06942005 CsVMV::HIO32.2 34.0027 109.7938 5 DX06942006 CsVMV::HIO32.2 31.9079 103.0297 5 DX06942007 CsVMV::HIO32.2 31.0441 100.2405 5 DX06942008 CsVMV::HIO32.2 30.5782 98.7361 5 DX06942009 CsVMV::HIO32.2 35.4122 114.3452 5 DX06942010 CsVMV::HIO32.2 32.6468 105.4156 5 DX06942011 CsVMV::HIO32.2 35.5334 114.7364 5 DX06942012 CsVMV::HIO32.2 31.0164 100.1512 5 DX06942014 CsVMV::HIO32.2 29.8991 96.5435 5 DX06942015 CsVMV::HIO32.2 33.7687 109.0383 5 DX06942016 CsVMV::HIO32.2 31.959 103.1948 5 DX06942017 CsVMV::HIO32.2 32.7295 105.6828 5 DX06942018 CsVMV::HIO32.2 32.3263 104.3809 5 DX06942019 CsVMV::HIO32.2 33.0989 106.8755 5 DX06942020 CsVMV::HIO32.2 29.9662 96.7602 5 DX06960001 None 28.8877 93.2776 5 DX06960002 None 33.7045 108.8311 5 DX06960003 None 29.816 96.275 5 DX06960004 None 32.7046 105.6022 5 DX06960005 None 31.3342 101.1775 5 DX06960006 None 31.0325 100.2031 5 DX06960007 None 32.8594 106.1021 5 DX06960008 None 28.4125 91.7432 5 DX06960009 None 30.4112 98.1969 5 DX06960010 None 30.5333 98.5913

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1. A method of producing a high oil phenotype in a plant, said method comprising: a) introducing into progenitor cells of the plant a plant transformation vector comprising a heterologous constitutive promoter operatively linked to a nucleotide sequence that encodes a HIO32.2 polypeptide comprising the amino acid sequence of SEQ ID NO:2, or having at least 95% sequence identity to the amino acid sequence of SEQ ID NO:2, to produce transformed cells overexpressing the HIO32.2 polypeptide; b) growing the transformed progenitor cells to produce a transgenic plant; and c) identifying a high oil phenotype in said transgenic plant by measuring oil content of the transgenic plant and selecting a transgenic plant that possesses a higher oil content relative to a plant of the same species that does not comprise the plant transformation vector.
 2. The method claim 1, wherein the nucleotide sequence encodes a HIO32.2 polypeptide consisting of an amino acid sequence having at least 95% sequence identity to the amino acid sequence of SEQ ID NO:2.
 3. The method of claim 1, wherein the nucleotide sequence that encodes the HIO32.2 polypeptide comprises the amino acid sequence of SEQ ID NO:2.
 4. The method of claim 3, wherein the nucleotide sequence that encodes the HIO32.2 polypeptide consists of the amino acid sequence of SEQ ID NO:2. 